1. Field of the Invention
The present invention relates to an optical coherence tomographic imaging apparatus, and in particular, to an optical coherence tomographic imaging apparatus having a coherent optical system used for medical application.
2. Description of the Related Art
Today, a variety of ophthalmic equipment using optical instruments is used. These are, for example, an anterior camera, a fundus camera, a confocal scanning laser ophthalmoscope (Scanning Laser Ophthalmoscope: SLO), etc. In particular, an optical coherence tomographic imaging apparatus (hereinafter referred to as an OCT apparatus) is to obtain a tomographic image of an object to be inspected at high resolution, and is now becoming a necessary and indispensable apparatus in specialty outpatient clinics for retina care.
The above-mentioned OCT apparatus uses low-coherence light as a light source. The light from the light source is divided into measurement light and reference light through a split optical path such as a beam splitter, etc. One of the light thus divided, the measurement light, is irradiated onto an object to be inspected such as an eye through a sample arm (measurement optical path), and return light thereof is guided to a detection position through a detection optical path. The return light is reflected light or scattered light that contains information on an interface in a direction of the light irradiated to the object to be inspected, etc. The other reference light is reflected by a reference mirror or the like through a reference arm (reference optical path), and is guided to the detection position. The return light and the reference light are caused to interfere with each other, and are analyzed so as to obtain information on a layer structure of the object to be inspected. In addition, it is possible to obtain a three-dimensional tomographic image by scanning low-coherence light in a two-dimensional manner.
Japanese patent application laid-open No. H11-325849 discloses an OCT apparatus used for medical application. Here, an optical spectrum is obtained by changing the position of a reference mirror three times in a discontinuous manner for the measurement of one point in an object to be inspected. It is possible to obtain a necessary optical spectrum in a desired area by performing one-dimensional scanning with the use of a scanner or the like. Finally, by analyzing these data, a two-dimensional tomographic image is obtained.